What is Project Glasswing and why it matters

In April 2026, Anthropic announced Project Glasswing — an initiative bringing together 12 key players from the technology world: Amazon Web Services, Apple, Broadcom, Cisco, CrowdStrike, Google, JPMorganChase, Linux Foundation, Microsoft, NVIDIA, and Palo Alto Networks. Their shared goal is to secure the planet's most critical software before attackers can exploit it.

The project's name references the butterfly Greta oto, known for its transparent wings. The metaphor is twofold: vulnerabilities hide in code in plain sight, much like transparent wings in nature, and at the same time, it reflects the transparency to which Anthropic is committed.

At the core of the project is Claude Mythos Preview — a currently non-public model that achieves capabilities in finding and exploiting software bugs that surpass all existing AI models and the vast majority of human experts. This is a model that literally changes the rules of cybersecurity.

What Mythos can do: a 27-year-hidden bug and five million tests that missed it

The results from the first month, which Anthropic published on May 22, 2026 in its first update, are breathtaking. The project's partners collectively found over 10,000 critical or high-severity vulnerabilities across the world's most important software.

Among the most remarkable findings are:

• A 27-year-old vulnerability in OpenBSD — an operating system considered one of the most secure in the world. The bug allowed an attacker to remotely crash any machine simply by connecting to it.
• A 16-year-old bug in FFmpeg — a library used by countless applications for video encoding. Automated testing tools hit this line of code five million times without ever detecting the flaw.
• Chaining of multiple vulnerabilities in the Linux kernel — the model autonomously discovered and combined them to escalate from regular user access to full control over the machine.

In the CyberGym benchmark, which simulates realistic cyberattacks, Mythos Preview scored 83.1% compared to 66.6% for the previous model Claude Opus 4.6. In SWE-bench Pro, testing the ability to solve real-world software tasks, it scored 77.8% (Opus 4.6: 53.4%).

Cloudflare, one of the partners, found 2,000 bugs in its critical systems (400 of them high or critical severity), with a false positive rate that their team said was better than human testers. Mozilla discovered and fixed 271 vulnerabilities in Firefox 150 — more than ten times what it found with the previous model, Opus 4.6.

A model that must not get out

Anthropic has decided not to release Mythos Preview publicly. The reason is simple: in the wrong hands, the model's capabilities could cause catastrophic damage. Instead, the company carefully selects who gets access to the model, granting it only to vetted partners within Project Glasswing.

This stance has led to several controversies. Anthropic denied access to the Pentagon — according to CEO Dario Amodei's statement, Defense Secretary Pete Hegseth refused to guarantee that the model would not be used for mass government surveillance or fully autonomous weapons. The dispute is now being handled by an appeals court.

Anthropic also said no to China, which requested access to Mythos. Two "no's" to two superpowers — at a time when technology companies routinely navigate between commercial interests and ethics, this is an exceptional stance.

The UK's AI Security Institute confirmed that Mythos Preview is the first model to independently solve both of their cyber ranges — simulations of multi-stage cyberattacks from start to finish.

What it means for Europe and Czechia

Project Glasswing has fundamental significance for European cybersecurity as well. The model found thousands of vulnerabilities in open-source projects that underpin the internet's infrastructure — and therefore also European banks, hospitals, and energy grids. Anthropic has already reported 530 critical bugs to open-source project maintainers, but the pace of fixes is lagging: the average time to patch a single critical bug is two weeks.

For Czech companies and institutions, the clear recommendation is: shorten security patch installation cycles to the absolute minimum. The era when weeks or months passed between discovering a vulnerability and exploiting it is over. With models at Mythos's level, an attacker can find and exploit a hole within minutes.

The European Union is simultaneously working on implementing the AI Act, which regulates similarly high-risk models. Project Glasswing shows that even companies themselves are beginning to understand the necessity of self-regulation — the question remains whether it will be enough.

Against the backdrop of these events, on May 23, 2026, US President Donald Trump revoked the executive order on AI security vetting under pressure from large technology companies, as reported by The Guardian. This raises further questions about who and how will oversee models with the potential to shift the global security balance.

What comes next

Anthropic plans to expand Project Glasswing with additional partners, including US and allied governments. The company is also putting 100 million dollars in credits toward model usage and 4 million dollars in direct grants to open-source organizations — of which 2.5 million dollars goes to Alpha-Omega and OpenSSF at the Linux Foundation and 1.5 million to the Apache Software Foundation.

After the research preview ends, Mythos Preview will be available to partners at 25 dollars per million input tokens and 125 dollars per million output tokens via the Claude API, Amazon Bedrock, Google Cloud Vertex AI, and Microsoft Foundry.

Going forward, Anthropic aims to develop sufficiently strong safety guardrails that will enable the safe deployment of Mythos-class models to the broader public as well — not just for cybersecurity, but also for other areas where similarly capable models will bring benefits.